Field of the Invention
This invention relates to a filter and matrix support useful in chromatography columns. More particularly, this invention relates to a filter support which may be readily provided for chromatography columns.
Chromatography is a commonly employed technique used to separate a biological or chemical material based upon the material""s physical or chemical properties. For example, proteins may be separated (fractionated) using column chromatography in which a mixture of proteins in a solution are passed through a vertical column containing a porous solid matrix. The speed of passage of the proteins through the column is influenced by the interaction of the proteins with the matrix. The proteins are retarded to varying degrees based upon their interaction with the column matrix. The proteins may be separated and/or purified from a heterogeneous mixture and separately collected as the different proteins exit the column.
The column matrix may be selected to discriminate materials based upon size, shape, electrical charge, or binding affinity for a particular substrate present on the matrix materials. For instance, ion-exchange columns may be packed with small beads or resin which carry a positive or negative charge. As a result, materials passing over the column are separated according to their charge properties.
Gel-filtration columns are packed with small porous beads and are used to separate a material, such as a protein, based upon size. Smaller molecules enter successive beads and thereby take longer to migrate along the column distance while materials too large to enter the interior of the beads flow rapidly through the column.
Affinity columns may be used to separate materials by attaching specific molecules, such as an enzyme, lectin or antibody, which will selectively interact with and bind target molecules passed over the column. Upon elution from the column, a purified fraction of the released target molecules may then be collected.
Traditionally, chromatography columns are made of borosilicate glass and are commercially available in various sizes ranging from 0.7-4.8 cm I.D. Such columns typically use a polyethylene bed support which is supplied with the column. However, the standard sizes of traditional liquid chromatography columns and accessories are not compatible with other standard lab glassware supplies. Further, some bed supports use a ceramic frit to support the separation matrix and are subject to clogging, flow rate changes over time, and are difficult to clean for reuse. Accordingly there is a need within the art for liquid chromatography columns which conforms to and may make use of standard laboratory glassware supplies.
A variety of chromatography columns and related accessories are known within the art. U.S. Pat. No. 5,893,971, incorporated herein by reference, is directed to a liquid chromatography apparatus in which a lower column end is attached to a retaining plate. Within the retaining plate, a frit holder is provided, external to the column, to provide support to the column matrix such as a resin or silica particulate.
In U.S. Pat. No. Re. 31,974, incorporated herein by reference, is directed to pressure chromatography. A multi-purpose end plug is used to seal and plug the column end.
In U.S. Pat. Nos. 3,771,659 and 4,692,243, both of which are incorporated herein by reference, disclose various filter holders and support members for retaining a resinous matrix within the separation column.
Despite the wide assortment of available apparatuses and teachings present within the art, there remains room for improvement and variation within the art liquid chromatography.
It is an object of this invention to provide an apparatus which facilitates the use of standard sized and configured laboratory glassware as a chromatography column.
It is a further object of this invention to provide a support structure for retaining a chromatography resin within the interior of a glass cylinder.
It is a further object of this invention to provide a chromatography support structure to which a back pressure may be applied to packed column, thereby clearing particulate from the matrix and reestablishing an improved flow rate of the column.
It is a further and more particular object of this invention to provide a stainless steel matrix holder, the holder defining a central opening and further defining a circumferential, reduced diameter groove engaged by a gasket such as an O-ring. The installed O-ring has an outer diameter which is greater than the bushing O.D. A mesh screen covers an upper surface and top opening of the bushing. When placed inside a glass column, the bushing can be inserted into the column and placed inside a ledge defined along the interior wall of a lower end of the column. When so placed, the bushing provides a liquid-tight seal around the periphery of the column. The mesh screen provides a support structure for a chromatography resin or other matrix.
These and other objects of the invention are accomplished by a chromatography support comprising: a resin support apparatus for a chromatography column comprising: a stainless steel cylinder having an outer diameter and an inner diameter, the outer diameter being greater than a height of the stainless steel cylinder, the cylinder defining a groove in an exterior wall of the stainless steel cylinder, the groove being substantially parallel to an upper and a lower rim of the stainless steel cylinder; an xe2x80x9cOxe2x80x9d-ring positioned within the groove, the xe2x80x9cOxe2x80x9d-ring having an outer diameter greater than the outer diameter of the stainless steel cylinder; and, a stainless steel mesh welded to an upper surface of the stainless steel cylinder and covering an opening defined by the stainless steel cylinder; wherein, when said stainless steel cylinder is placed within a receiving ledge formed on an interior surface of a volumetric cylinder, the xe2x80x9cOxe2x80x9d-ring provides a fluid tight seal between the stainless steel cylinder and the inner wall of the graduated cylinder, the stainless steel mesh providing a support platform adapted for receiving a supply of a chromatography matrix.
Further objects of the invention are provided by a method of constructing a chromatography column comprising: supplying a glass tubing having an upper opening and a lower opening; forming a reduced inner diameter taper along an interior surface of the glass tubing; positioning a steel cylinder having an inner diameter and an outer diameter onto the taper, the steel cylinder further defining an xe2x80x9cOxe2x80x9d-ring positioned within a circumferential groove, the xe2x80x9cOxe2x80x9d-ring having an outer diameter greater than an inner diameter of the glass cylinder; attaching to an upper surface of the steel cylinder a stainless steel mesh, the mesh extending across an upper opening defined by the stainless steel cylinder; introducing a supply of a chromatography matrix material into the volumetric cylinder, the matrix being supported along a mesh carried by the steel cylinder.